fs/9p/xattr.c

   1 // SPDX-License-Identifier: LGPL-2.1
   2 /*
   3  * Copyright IBM Corporation, 2010
   4  * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
   5  */
   6
   7 #include <linux/module.h>
   8 #include <linux/fs.h>
   9 #include <linux/sched.h>
  10 #include <linux/uio.h>
  11 #include <net/9p/9p.h>
  12 #include <net/9p/client.h>
  13
  14 #include "fid.h"
  15 #include "xattr.h"
  16
  17 ssize_t v9fs_fid_xattr_get(struct p9_fid *fid, const char *name,
  18                            void *buffer, size_t buffer_size)
  19 {
  20         ssize_t retval;
  21         u64 attr_size;
  22         struct p9_fid *attr_fid;
  23         struct kvec kvec = {.iov_base = buffer, .iov_len = buffer_size};
  24         struct iov_iter to;
  25         int err;
  26
  27         iov_iter_kvec(&to, READ, &kvec, 1, buffer_size);
  28
  29         attr_fid = p9_client_xattrwalk(fid, name, &attr_size);
  30         if (IS_ERR(attr_fid)) {
  31                 retval = PTR_ERR(attr_fid);
  32                 p9_debug(P9_DEBUG_VFS, "p9_client_attrwalk failed %zd\n",
  33                          retval);
  34                 return retval;
  35         }
  36         if (attr_size > buffer_size) {
  37                 if (!buffer_size) /* request to get the attr_size */
  38                         retval = attr_size;
  39                 else
  40                         retval = -ERANGE;
  41         } else {
  42                 iov_iter_truncate(&to, attr_size);
  43                 retval = p9_client_read(attr_fid, 0, &to, &err);
  44                 if (err)
  45                         retval = err;
  46         }
  47         p9_fid_put(attr_fid);
  48         return retval;
  49 }
  50
  51
  52 /*
  53  * v9fs_xattr_get()
  54  *
  55  * Copy an extended attribute into the buffer
  56  * provided, or compute the buffer size required.
  57  * Buffer is NULL to compute the size of the buffer required.
  58  *
  59  * Returns a negative error number on failure, or the number of bytes
  60  * used / required on success.
  61  */
  62 ssize_t v9fs_xattr_get(struct dentry *dentry, const char *name,
  63                        void *buffer, size_t buffer_size)
  64 {
  65         struct p9_fid *fid;
  66         int ret;
  67
  68         p9_debug(P9_DEBUG_VFS, "name = %s value_len = %zu\n",
  69                  name, buffer_size);
  70         fid = v9fs_fid_lookup(dentry);
  71         if (IS_ERR(fid))
  72                 return PTR_ERR(fid);
  73         ret = v9fs_fid_xattr_get(fid, name, buffer, buffer_size);
  74         p9_fid_put(fid);
  75
  76         return ret;
  77 }
  78
  79 /*
  80  * v9fs_xattr_set()
  81  *
  82  * Create, replace or remove an extended attribute for this inode. Buffer
  83  * is NULL to remove an existing extended attribute, and non-NULL to
  84  * either replace an existing extended attribute, or create a new extended
  85  * attribute. The flags XATTR_REPLACE and XATTR_CREATE
  86  * specify that an extended attribute must exist and must not exist
  87  * previous to the call, respectively.
  88  *
  89  * Returns 0, or a negative error number on failure.
  90  */
  91 int v9fs_xattr_set(struct dentry *dentry, const char *name,
  92                    const void *value, size_t value_len, int flags)
  93 {
  94         int ret;
  95         struct p9_fid *fid;
  96
  97         fid  = v9fs_fid_lookup(dentry);
  98         if (IS_ERR(fid))
  99                 return PTR_ERR(fid);
 100         ret = v9fs_fid_xattr_set(fid, name, value, value_len, flags);
 101         p9_fid_put(fid);
 102         return ret;
 103 }
 104
 105 int v9fs_fid_xattr_set(struct p9_fid *fid, const char *name,
 106                    const void *value, size_t value_len, int flags)
 107 {
 108         struct kvec kvec = {.iov_base = (void *)value, .iov_len = value_len};
 109         struct iov_iter from;
 110         int retval, err;
 111
 112         iov_iter_kvec(&from, WRITE, &kvec, 1, value_len);
 113
 114         p9_debug(P9_DEBUG_VFS, "name = %s value_len = %zu flags = %d\n",
 115                  name, value_len, flags);
 116
 117         /* Clone it */
 118         fid = clone_fid(fid);
 119         if (IS_ERR(fid))
 120                 return PTR_ERR(fid);
 121
 122         /*
 123          * On success fid points to xattr
 124          */
 125         retval = p9_client_xattrcreate(fid, name, value_len, flags);
 126         if (retval < 0)
 127                 p9_debug(P9_DEBUG_VFS, "p9_client_xattrcreate failed %d\n",
 128                          retval);
 129         else
 130                 p9_client_write(fid, 0, &from, &retval);
 131         err = p9_fid_put(fid);
 132         if (!retval && err)
 133                 retval = err;
 134         return retval;
 135 }
 136
 137 ssize_t v9fs_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
 138 {
 139         return v9fs_xattr_get(dentry, NULL, buffer, buffer_size);
 140 }
 141
 142 static int v9fs_xattr_handler_get(const struct xattr_handler *handler,
 143                                   struct dentry *dentry, struct inode *inode,
 144                                   const char *name, void *buffer, size_t size)
 145 {
 146         const char *full_name = xattr_full_name(handler, name);
 147
 148         return v9fs_xattr_get(dentry, full_name, buffer, size);
 149 }
 150
 151 static int v9fs_xattr_handler_set(const struct xattr_handler *handler,
 152                                   struct user_namespace *mnt_userns,
 153                                   struct dentry *dentry, struct inode *inode,
 154                                   const char *name, const void *value,
 155                                   size_t size, int flags)
 156 {
 157         const char *full_name = xattr_full_name(handler, name);
 158
 159         return v9fs_xattr_set(dentry, full_name, value, size, flags);
 160 }
 161
 162 static struct xattr_handler v9fs_xattr_user_handler = {
 163         .prefix = XATTR_USER_PREFIX,
 164         .get    = v9fs_xattr_handler_get,
 165         .set    = v9fs_xattr_handler_set,
 166 };
 167
 168 static struct xattr_handler v9fs_xattr_trusted_handler = {
 169         .prefix = XATTR_TRUSTED_PREFIX,
 170         .get    = v9fs_xattr_handler_get,
 171         .set    = v9fs_xattr_handler_set,
 172 };
 173
 174 #ifdef CONFIG_9P_FS_SECURITY
 175 static struct xattr_handler v9fs_xattr_security_handler = {
 176         .prefix = XATTR_SECURITY_PREFIX,
 177         .get    = v9fs_xattr_handler_get,
 178         .set    = v9fs_xattr_handler_set,
 179 };
 180 #endif
 181
 182 const struct xattr_handler *v9fs_xattr_handlers[] = {
 183         &v9fs_xattr_user_handler,
 184         &v9fs_xattr_trusted_handler,
 185 #ifdef CONFIG_9P_FS_POSIX_ACL
 186         &v9fs_xattr_acl_access_handler,
 187         &v9fs_xattr_acl_default_handler,
 188 #endif
 189 #ifdef CONFIG_9P_FS_SECURITY
 190         &v9fs_xattr_security_handler,
 191 #endif
 192         NULL
 193 };